Fuse assembly



Aug. 29, 1939.

T. F. JQHNsoN 2,171,179

FUSE ASSEMBLY Filed July 22, 1957 2 Sheets-Sheet l 43 I ry M1 L gig! Z3/7 ./40 *1 3 MZ 9 i@ 30 1' I A I f4# gnb I Y0 l Q 9 f z5 \/f 22 l Jl 24!/6 if f2 I" .J #ffii /g j# f5 a 26 5 T. F. JOHNSON FUSE ASSEMBLY Aug.29, 1939.

.Filed July 22, 1937 2 Sheets-Sheet 2 Patented Aug. 29, 1939 UNITEDSTATES TENT OFFiCE 9 Claims.

This invention relates to fuses for high tension transmission lines and,among other objects, aims to provide a greatly simplified, relativelyrugged and reliable detachable transformer fuse particularly designedfor use in rural electrication installations. The main idea is toprovide a fuse of this type suspended from a single support and havingwedge action contact so that it will not loosen due to ordinary windvibration and the like but can easily be removed and/or replaced byusing the proper stick.

Other aims and advantages of the invention will appear in thespecification, when considered in connection with the accompanyingdrawings,

wherein:

Fig. 1 is a side elevation of the preferred form of fuse assemblysupported by a single insulator;

Fig. 2 is a front elevation of the fuse assembly shown in Fig. 1;

Fig. 3 is a sectional view taken on the line 3 3 of Fig. l;

Fig. 4 is a side elevation, partly in section, of the fuse assembly, butshowing it suspended from a transmission line;

9.5k Fig. 5 is a front View of the fuse assembly shown in Fig. 4;

Fig. 6 is a bottom plan View of Fig. 4; and

Fig. 7 is a top plan view of a stirrup support in the fuse assemblyshown in Fig. 4.

Referring particularly to Figs. 1 to 3, the fuse assembly there shown isprimarily intended for use on rural transmission lines which are usuallysupported on wood poles. Rural connections are usually made by mountinga transformer on a pole or a wooden cross arm on the pole. In thisinstance, a transformer (not shown), is adapted to be mounted on a crossarm IB. The fuse assembly is also shown as being supported by the crossarm and is adapted to be connected to the line by a tap conductor I!which, in turn, may be tapped to the line by an ordinary line clamp (notshown).

Referring to Fig. l, the fuse assembly is shown as being mounted on thecross arm by means of a single insulator I2 having the usual attachingbolt I3 extending through the arm. On the outer portion of the insulatorthere is mounted a stirrup I4 having a saddle I5 secured to theinsulator by a U-bolt I6. The stirrup has a terminal connection for thetap conductor I I. The outer end of the stirrup is shown as beingbifurcated and presents vertically extending channel shaped wings I1having a flat contact surface i8. The outer ends of the two arms I9 ofthe stirrup are v connected by a cross bar 20 which also acts to (Cl.20W- 115) complete a wedge receiving socket for rigidly suspending thefuse unit.

In this example, the fuse unit is shown as comprising an ordinary fusetube 2i on the upper end of which is suitably secured a collar 22 carry-5 ing an integral hook-shaped bracket 23 which has a wedge shapedcontact member 24 preferably T-shaped in cross section and presenting anouter relatively wide Vertical flange 25 adapted to engage and be seatedfirmly against the wedge lo contact surface I8 of the stirrup. The innerinclined edge of the wedge is merely designed to engage the surface ofthe cross bar 20 to exert wedging action against the contact surface.

ln this instance, the collar or ferrule 22 has l5 an integral eye 2t toreceive the hook of a linemans stick so that the fuse unit may beremoved by raising the wedge ZM out of the stirrup. The fuse element 2lis shown as being electrically connected to the ferrule or collar andthrough 20 it to the wedge by means of a clamping member 28 held againsta metal washer 29 on the upper end of the fuse tube. The clamp issecurely gripped against the washer by means of an ordinary nut 3@ on astud 3l. The fuse element 25 2l passes through the Washer and has a head3?. on itsy upper end. It is adapted to be replaced when it is blown.

At the lower end of the fuse tube there is shown an elongated bracket 33to one end of 30 which is connected a transformer tap conductor 3ft. Theopposite end of the bracket extends some distance laterally from the endof the tube and carries a pivotally mounted flip-out link or arm 35having a bifurcated free end through 35 which the fuse element extends.The lower end oi the fuse element passes around the outer end of thebracket and is shown as being electrically connected thereto by means ofanother nut 36 on a bolt Si extending upwardly through an open- 40 ingin the bracket. The arrangement oi the fuse element and flip-out arm issuch that', when the fuse link blows out the arm 35 will immediatelyswing down and assist in withdrawing the burned ofi lower portion of thefuse element (see the 45 dotted positions of these parts in Fig. 4). Inthis instance, there is shown a small coil spring 38 having one endengaging the arm 35 to accelerate its flip-out movement. When the fuseelement blows and the parts are in the position 50 shown in dotted linesin Fig. 4. a lineman can quickly determine that the fuse has blown.lncidentally, there is suicient slack provided in the transformer tapconductor 34 to permit the fuse unit to be lifted out as previouslyexplained. 55

Cin

It is only necessary that the lineman engage the eye Z of the fuse unitwith his fuse removing stick and either replace the fuse element thereinor substitute a new fuse unit. This operation may be performed by anyunskilled mechanic.

In the form of stirrup described above, it is sometimes desirable toprovide a spark gap or path to ground for lightning. To this end, thesaddle I5 is shown as having an integral vertical arm or conductor 39. Asecond vertical arm 40 is clamped against the wooden cross arm l0 by ashoulder il on the insulator bolt I3. The arm l0 carries an adjustablehorizontal rod 42 at its upper end, the free end of the rod being spacedfrom the arm 39 to provide a suitable gap. The inner end of the rod isscrew threaded and extends through the arm 40. Nuts 43 on opposite sidesof the arm 4U hold the rod in adjusted position. y

Referring to the fuse assembly shown in. Figs. 4 to 7 inclusive, thefuse unit is adapted to be suspended from the transmission line insteadof a cross arm. The fuse unit and its wedge shaped Contact member areidentical with the form shown in Figs. l to 3. However, the stirrup I4'in this instance has an integral vertical arm All which carries acontact lamp 45 adapted to be tightened on the transmission wire 46 bymeans of an ordinary clamping bolt All'. This form of fuse assembly iswell adapted to be suspended at any point from a transmission linebetween its posts or supports and the transformer tap conductor 34 maylead to a large transformer mounted on a platform or a base on theground. Even though the wind may swing the transmission wire and vibratethe fuse unit, the wedge contact will prevent the fuse unitl from beingloosened. In fact, the more the fuse unit vibrates, the tighter will bethe wedging engagement and the better the contact. The fuse unit may beinserted in and removed from the stirrup in the same manner as explainedin connection with Figs. l to 3. The line clamp may be of anyapproved'type and may be such as to be easily removable with an ordinaryswitch stick or other suitable linemans implement.

From the foregoing description, it will be seen that the improved fuseassembly is very simple and rugged in its` design. It is dependable inoperation. It has no complicated parts or spring jaws and extrasupports. It is easily manipulated by an Vunskilled mechanic, and it canbe installed at a very low cost. In fact, it is eminently adapted foruse in all rural electrication projects.

Obviously, the present invention is not restricted to the particularembodiment thereof herein shown and described. Moreover, it is notindispensable that all the features of the invention be used conjointly,since they may be employed advantageously in various combinations andsub-combinations.

What is claimed is:

l. In a fuse assembly 0f the class described, a

` horizontal metal stirrup having a vertical contact face and ahorizontal cross'bar spaced therefrom providing a fuse support; and avertical fuse unit suspended from said stirrup having a self-tightening,wedge shaped contact member inserted through the upper side of thestirrup and removably engaged between the contact face and the crossbar.

2. In a fuse assembly of the class described, a

Y support; an insulator on'the support; a horil' zontal stirrup clampedon the insulator and having spaced wedge receiving portions; means onthe stirrup for connecting it to a transmission line; a vertical fuseunit; and hook shaped wedge means on the upper end of the fuse unitengageable with the spaced wedge receiving portions on the stirrup forremovably suspending it from the stirrup.

3. In a fuse assembly of the class described, a xed supporting member; avertical insulated fuse tube; contact means on the upper end oi the tuberemovably but normally rigidly connecting it to and suspending it solelyfrom the supporting member; a fuse element within the tube having itsupper end electrically connected to the contact means; a metal bracketsecured to the lower end of the tube; and means on the bracket forsecuring the other end of the element and maintaining the element taut,said means including a spring urged member arranged to expel the lowerportion of the element when it blows.

4.v In a fuse assembly of the class described, a support; an insulatoron the support; a horizontal stirrup having a cross bar clamped on theinsulator; means on the stirrup for connecting it to a transmissionline; a vertical arm on the stirrup; an adjustable member carried by theinsulator support and spaced from the arm to provide a spark gap; avertical fuse unit; and self-tightening means including a wedge shapedhook portion on the fuse unit engageable with the cross bar of thestirrup for removably suspending it from the stirrup.

5. In a fuse assembly of the class described, a stationary support; aninsulator secured to the support; a horizontal stirrup clamped on theinsulator; means on the stirrup for connecting it to a transmissionline; a vertical fuse unit; and a hook shaped bracket on the upper endof the fuse unit having a self-tightening wedge portion removablyengaged in the stirrup.

6. In a fuse assembly of the class described, a stationary support; aninsulator secured to the support; a horizontal stirrup clamped on theinsulator; means on the stirrup for connecting it to a transmissionline; a vertical fuse unit; selitightening wedge means on the fuse unitengageable with tlie stirrup for removably suspending it from thestirrup; and means at the lower end of the fuse unit automatically toremove a p0rtion of the fuse element when it blows.

'7. In a fuse assembly of the class described, a fuse unit having ahook-shaped contact member at one end; a supporting stirrup forsuspending the fuse unit having outwardly diverging horizontal arms anda cross bar between the arms; a vertical ange member on the stirrup toprovide a guiding and contact face coacting with said hook-shapedcontact member; and means on the stirrup for connecting it to atransmission line.

8. In a fuse assembly of the class described, a fuse unit having contactmeans at its upper end by which-it may be suspended; a supportingstirrup having outwardly diverging horizontal arms and a cross barbetween the arms; a vertical flange member on the stirrup to provide aguiding and contact face coacting with said contact means to support theiuse unit; an integral arm extending upwardly from said stirrup; and

means at the upper end of the arm to'secure it to a transmission line.

9. In a fuse assembly of the class described, a fuse unit; a supportingstirrup for suspending the fuse unit having outwardly diverginghorizontal arms and a cross bar between the arms; a. vertical flangemember on the stirrup to provide a guiding and Contact face; a hook likewedge shaped Contact member at the upper end of the fuse unit insertedthrough the upper side of the stirrup between the cross bar and theflange member; an integral arm extending up- Wardly from the stirrup;and clamp means on the upper end of the arm to connect the arm to atransmission line so that the stirrup and fuse unit are supported solelyby the line.

TOMLINSON FORT JOHNSON.

